2016-2018 Lincoln MKX Brake Caliper Problems and Replacement

By Core Brake Parts Tech Team — Circleville, OH warehouse

Most "caliper problems" on a 2016-2018 Lincoln MKX fall into three groups: rear calipers that will not let go because of the electric parking brake motor mounted on them, slide pins that seize and wear one pad faster than the other, and fluid leaks that turn out to be a recalled brake hose rather than the caliper itself. Before you buy a caliper, check the recall status on the VIN and read the warning messages in the cluster, because two of those three complaints are not a bad caliper at all.

How the brakes on a 2016-2018 MKX are built

The second-generation MKX shares its brake hoses, and the recalls that go with them, with the 2015-2018 Ford Edge. It uses four-wheel disc brakes with sliding calipers. The front calipers are purely hydraulic. The rear calipers are different: each one carries an electric parking brake motor. The factory parts catalog for the 2016 MKX lists separate left and right parking brake motors, plus the O-ring that seals each motor, in the same rear brake disc and caliper group as the calipers, pads and slide pin bolts.

There is no parking brake pedal or handle on this generation. The owner's manual states that the electric parking brake replaces the conventional handbrake and is operated by a switch on the instrument panel. That one design choice drives most of the rear caliper service questions owners run into.

Common MKX caliper symptoms and what they usually mean

Rear brake will not release, or a park brake warning

The MKX owner's manual describes several cluster messages tied to the rear brakes: "Park Brake Malfunction Service Now" when the system detects a condition that needs service, and "Park Brake Maintenance Mode" when the system is in its service state. It also warns that if the brake system warning lamp keeps flashing after you apply the electric parking brake, or stays on for more than four seconds after release, there could be a problem with the braking system and the vehicle should be checked.

Before you blame the caliper, check the battery. The manual is explicit that you cannot apply or release the electric parking brake if the battery is low or has no charge. A weak battery can leave the rear brakes clamped or throw a parking brake fault that looks like a failed motor. Ford has also traced electric park brake warnings on a related Ford SUV to rear wiring harnesses damaged where they run close to the wheels, so inspect the connector and harness at each rear caliper before replacing anything.

Pulling, dragging, heat, or one pad worn to the backing plate

This is the classic sliding-caliper failure. Brake & Front End, a trade magazine for brake technicians, lists bent or binding mounting pins, worn slides, damaged brackets, swollen or hardened guide seals, and lack of lubrication as the reasons a caliper stops moving freely. The results are uneven pad wear, one pad wearing much faster than the other, and abnormal caliper operation. In practice you will see one pad on a wheel worn far past its partner, or a wheel that is noticeably hotter than the others after a drive.

Low pedal, fluid on the inside of the wheel, brake fluid warning

Do not assume this is a leaking caliper piston seal. The 2016-2018 MKX is covered by two NHTSA safety recalls for the flexible brake hoses that feed the calipers (details in the next section). A ruptured hose leaks fluid right next to the caliper and looks, at a glance, like a caliper leak. A true caliper leak shows fluid coming from the piston boot or the bleeder, not from the rubber hose.

Grabby, overly sensitive brakes at low speed

If the complaint is that the brakes bite too hard in parking lots or in cold, wet weather, the caliper is probably not the cause. Ford Special Service Message 45857 covers some 2016 MKX vehicles built on or before March 23, 2016 with overly sensitive brake application, and the fix in that message is an updated brake booster, not calipers.

The two brake hose recalls on the 2016-2018 MKX

Anyone diagnosing a leak or a soft pedal on this vehicle needs to know about these two campaigns, because the hose is the part bolted directly to the caliper.

• NHTSA recall 20V-469 (Ford 20S42), front brake hoses. Covers 2016-2018 MKX built from November 11, 2014 to December 21, 2017 (45,989 of the 2016 models, 28,676 of the 2017 models and 8,269 of the 2018 models). Ford's report says the front brake jounce hoses can rupture from fatigue of the internal reinforcement braid during suspension and steering movement, causing a progressive fluid leak, longer pedal travel and reduced deceleration. The remedy is new front hoses with a revised braid material.
• NHTSA recall 25V-544 (Ford 25S87), rear brake hoses. Covers 84,412 2016-2018 MKX built from November 11, 2014 to December 21, 2017. A ruptured rear jounce hose causes a progressive fluid leak, longer pedal travel and longer stopping distances. Ford noted a significantly reduced repair rate after the hose braid material changed from polyvinyl alcohol to polyethylene terephthalate in December 2017.

Both reports say the driver may notice a change in pedal feel and travel, and the red brake fluid warning light can illuminate. Recall work is done by a Ford or Lincoln dealer at no charge, so run your VIN before paying for hoses or a caliper.

Replacing an MKX caliper: what the job involves

Front calipers

A front caliper swap is a normal bolt-on job: support the vehicle, remove the wheel, disconnect the hose and limit fluid loss, unbolt the caliper, transfer or replace the pads, install the new caliper with clean, lubricated slide pins, and bleed. Use new sealing washers on the hose fitting, and torque every fastener to the value in the factory service manual.

Rear calipers and the electric parking brake

The rear is where people get into trouble. On a motor-on-caliper design the parking brake motor is linked to the piston, so the piston cannot simply be pushed back with a clamp while the motor is holding it out. Brake & Front End points out that automakers build bi-directional scan tool routines to retract the parking brake so pads can be replaced, and warns that shortcuts such as jumping power to connector pins can set malfunction codes and damage the unit. The MKX cluster has a "Park Brake Maintenance Mode" message for exactly this service state.

The practical sequence is: put the parking brake into maintenance mode with a capable scan tool or the factory procedure, confirm the message, then move the motor from the old caliper to the new one (or use the motor supplied with it), reinstall the motor with a new O-ring, bleed the brakes, and exit maintenance mode. Then apply and release the parking brake several times and confirm the warning lamp behaves as the owner's manual describes.

Bleeding and fluid

The MKX owner's manual specifies DOT 4 Low Viscosity (LV) brake fluid meeting Ford specification WSS-M6C65-A2 and warns that using another fluid may degrade brake performance. It also says to keep the fluid clean and dry. After any caliper replacement, bleed that corner until clean, bubble-free fluid comes out, and keep the reservoir between the MIN and MAX marks.

What to replace at the same time

• Pads on both sides of the axle. A seized caliper usually ruins its pads, and pads are replaced in axle sets so the vehicle brakes evenly. See our brake pads.
• Rotors if they are scored, heat-spotted, or below minimum thickness. A dragging caliper overheats the rotor. Browse replacement brake rotors.
• Slide pins, boots and clips. Brake & Front End recommends replacing all mounting hardware and using a high-temperature caliper lubricant on sleeves, bushings and sliding surfaces. A brake hardware kit covers this.
• Brake hoses, if not already replaced under recall. Check both recalls first; if the work is done, still inspect the hoses for cracking and swelling. See brake hoses.
• The opposite caliper, only if it is also sticking or leaking. Calipers do not have to be replaced in pairs by rule, but if both are original and one has seized, the other is often not far behind.

If you are doing pads and rotors on both axles at once, a matched set is simpler than buying pieces. We carry a 2016-2018 Lincoln MKX front and rear brake kit, and individual units are in our brake calipers collection.

How hard is the job?

A front caliper on the MKX is a moderate DIY job for someone who has done brakes before: basic hand tools, a torque wrench and a way to bleed the system. The rear is a step harder only because of the parking brake motor. If you do not have a scan tool that can put the MKX electric parking brake into maintenance mode, or you are not confident in the factory procedure, this is the part of the job to hand to a shop. Forcing the piston back against the motor is the most common way DIY rear brake jobs on this generation go wrong.

Frequently Asked Questions

Why won't the rear caliper piston on my MKX push back?

The electric parking brake motor on the rear caliper holds the piston's position. It must be retracted, through maintenance mode with a scan tool or the factory procedure, before the piston will compress. Forcing it can damage the motor or the caliper mechanism.

Is there a recall on the 2016-2018 Lincoln MKX brake calipers?

Not on the calipers themselves. The MKX is covered by recall 20V-469 for the front brake hoses and 25V-544 for the rear brake hoses. Both hoses connect directly to the calipers, so a hose leak is easy to mistake for a caliper leak.

Can a weak battery cause a parking brake fault on the MKX?

Yes. The owner's manual states the electric parking brake cannot be applied or released if the battery is low or has no charge. Test and charge the battery before condemning a caliper or motor.

Do I have to replace both rear calipers at once?

No. Replace the failed caliper, and replace pads on both sides of the axle. Replace the other caliper only if it also shows sticking, leaking or a torn boot.

What brake fluid does the 2016-2018 MKX use?

Ford specifies DOT 4 Low Viscosity (LV) High Performance Brake Fluid meeting WSS-M6C65-A2. Use it when bleeding after a caliper replacement.

My brakes feel too grabby at low speed. Is that a caliper?

Usually not. Ford Special Service Message 45857 addresses overly sensitive braking on some early 2016 MKX vehicles with an updated brake booster. Have a dealer check whether it applies to your VIN.

Sources

1. NHTSA Part 573 Safety Recall Report 20V-469 - front brake hose recall: MKX build dates, units, cause and symptoms
2. NHTSA Part 573 Safety Recall Report 25V-544 - rear brake hose recall: MKX units, braid material change, symptoms
3. Ford Special Service Message 45857 (via NHTSA) - overly sensitive brake application fixed with an updated booster
4. Ford TSB 17-0005 (via NHTSA) - electric park brake warnings traced to damaged rear harnesses near the wheels
5. 2018 Lincoln MKX Owner's Manual (Ford) - electric parking brake operation, messages, battery warning, brake fluid spec
6. 2016 Lincoln MKX rear brake discs and calipers parts diagram - parking brake motors and O-rings in the rear caliper group
7. Brake & Front End: Electronic Parking Brake Diagnostics - motor-on-caliper retraction and what not to do
8. Brake & Front End: Bent or Binding Mounting Pins - sliding caliper failure causes, symptoms and hardware replacement